1. Field of the Invention
The present invention relates generally to a multicolor printing press, in which a plurality of printing sections are vertically arranged in spaced apart relationship for establishing a multi-stage printing press. Further particularly, the invention relates to a multicolor printing press with enhanced registering between respective stages of individual color printing.
2. Description of the Related Art
Japanese Unexamined Patent Publication (Kokai) No. 3-1946 discloses a construction of a multicolor printing press, in which a plurality of printing devices are vertically arranged in spaced apart relationship. The above-identified publication also discloses a register position adjusting means which minimizes register error of printing patterns between the printing sections. The printing register position adjusting means in the shown construction comprises at least means for adjusting along an axial direction of each plate cylinder relative to a corresponding blanket cylinder, for each of the printing sections.
However, in the prior art, a reference color for adjustment of register position is not fixed in multicolor printing. Therefore, it is possible that the reference color is differentiated for every cycle of printing operation to require adjustment of the register position every time the reference color is differentiated. For example, it can be experienced that, during adjustment of register position of respective plate cylinders in respective printing section in order with taking a certain color as the reference color, the adjustment of register position cannot be completed even at the allowable limit of adjustment for one of the colors to require modification of the original plan. Typically, in such case, the color for which adjustment of register position fails, is taken as the reference color to perform register position adjustment again. Such procedure clearly degrades efficiency of printing operation and increases lost paper due to printing with faulty registering.